Routine oil changes in internal combustion engines are known to prolong engine life by maintaining oil in a condition to better protect moving components of an engine. After extended use, engine oil is often broken down by exhaust gasses that escape the combustion chambers of an engine and then contact the engine oil. These gasses can cause the oil to break down from its original state and thus reduce the amount of protection the oil can offer to the engine.
It is known in the prior art to regularly change engine oil to remove used, broken down oil and replace it with fresh oil in order to protect an engine. In particular, it is known in the prior art to accomplish this by draining the oil from an oil tank and/or pan, refilling the oil tank and/or pan, and replacing the oil filter. However, this method can leave residual used oil in various portions of a lubrication system that are not readily drained. Such used oil can then mix with fresh oil that has been refilled into the engine. Mixing of the used oil with the fresh oil can cause the fresh oil to break down faster than it would otherwise. This mixing can also alter the characteristics of the fresh oil and thus reduce the amount of protection that the fresh oil can provide to the engine.
Many internal combustion engines have either a wet sump lubrication system or a dry sump lubrication system to circulate oil to various components in the engine for lubrication and cooling. A wet sump engine may have an oil pan located near a lower most portion of the engine for collecting and retaining the oil that is circulated throughout the engine during operation. An oil pump is used to draw oil from the oil pan and direct it through internal passageways within the engine, typically including passageways in the engine block and the cylinder head. These passageways deliver the oil to locations in the engine that require lubrication and/or cooling. For example, oil may be delivered to the pistons, valves, bearings, gears, and other components having parts that move relative to one another requiring lubrication and/or cooling. Once the oil has been delivered to these components it is returned, typically by gravity, back to the oil pan for recirculation throughout the engine.
Dry sump lubrication systems differ from wet sump systems in that much of the oil is retained in an oil tank that is remote from the oil pan and may even be remote from the engine itself. In these systems, oil is drawn from the oil tank and is pumped through internal passageways of the engine by a primary oil pump to reach the components that may require cooling or lubrication. Like in wet sump systems, the oil may be allowed to return to the oil pan, via gravity, once it has lubricated or cooled the appropriate component. However, an additional oil pump, often called a scavenging pump, draws the engine from the oil pan and delivers it back to the oil tank for subsequent recirculation by the primary oil pump. In this manner, a minimal amount of oil is retained in the oil pan or the ‘dry sump’. In such dry sump systems, the oil may be filtered when it is passed from the oil pan to the oil tank. However, some dry sump engines may filter the oil between the primary oil pump and the passageways of the engine or at other points within the lubrication system in addition to, or in place of filtering the oil in between the dry sump and the oil tank.